linux-omap3: Bump SRCREV to 2.6.28-rc6
linux-omap3: Bump SRCREV to 2.6.28-rc6

yyli/overo-oe,scottellis/overo-oe,yyli/overo-oe,nzjrs/overo-openembedded,yyli/overo-oe,John-NY/overo-oe,nzjrs/overo-openembedded,John-NY/overo-oe,nzjrs/overo-openembedded,yyli/overo-oe,nzjrs/overo-openembedded,John-NY/overo-oe,scottellis/overo-oe,nzjrs/overo-openembedded,John-NY/overo-oe,John-NY/overo-oe,nzjrs/overo-openembedded,scottellis/overo-oe,scottellis/overo-oe,yyli/overo-oe,yyli/overo-oe,scottellis/overo-oe,yyli/overo-oe,scottellis/overo-oe,yyli/overo-oe,nzjrs/overo-openembedded,John-NY/overo-oe,scottellis/overo-oe,John-NY/overo-oe